I just finished reading through this post in its entirety and I'm still digesting it for the most part. Below I'll share some thoughts.
Everything you said about the "us versus them" problem is true. Whether it's natural or artificial is up for debate. Regardless, it's our responsibility as writers, actors and story-tellers to make sure that this distance between different types of roleplayers is lessened.
Your Responsibility Toward Enjoyment
The point you made about how people ought to ensure that the other party enjoys the roleplay is something I wholeheartedly agree with. Roleplay is a form of improvisation, and when doing improv in groups, all parties must build off each other's actions. Avoiding a brick-wall is the goal, and keeping the flow going is the method. In order to keep the flow going, you have to offer sufficient stimuli to guarantee that the opposite party can continue the "act" or in our case the "roleplay".
For example, a hostage situation. Party A, the hostage, responds to the actions of Party B with vigour and engagement, enabling B to respond with the same amount of engagement. This wouldn't be possible if Party A just sat there and went "screw this" and offered the most lacklustre responses possible. The same goes vice-versa.
Roleplay is a collaborative experience, and we all share a responsibility towards enjoyment.
There is nothing inherently wrong with Text-RP in theory. Coming from a long history of Garry's Mod and World of Warcraft Text-RP, I can understand fully the appeal of Text-RP. It enables you to explore a character that you perhaps couldn't have acted through your voice alone. Personally, I roleplay with a mix. I always say what Roma says over VOIP, but when it comes to actions - smoking a cigarette, searching someone's pockets or running a hand through his hair - it goes through text. The problem with Text-RPers arises when there is a high-stakes situation or a fast-paced situation and they're not able to convey their characters in appropriate time. Furthermore, to properly Text-RP a level of writing skill comes into play which includes the use of descriptive words and being able to type in a pace that can keep up with people who use VOIP to roleplay.
You seemed to raise one of my issues about Text-RP in a different context in your post, too:
This largely isn't possible with Text-RPers. Sure, you can through in a ** Johnny speaks with a shaky voice, or a ** Jacky looked down as he spoke. But with most of my encounters with Text-RPers, descriptive emotes such as those are just not present. Voice will always trump text in portraying emotion in DayZRP.
This isn't only due to one's inability due to pacing, but it is also due to the limitations of DayZ. It doesn't really support "text" as a valid form of communication. The character limit is laughably small, and the size of the text-box requires players to literally squint to read it properly. The absence of a /me or a /it command is disappointing, too.
I'd like to mention one more thing: the use of "camp-fire roleplay" is outdated and doesn't account for the roleplay that occurs in most "camp-fire roleplay" circles. I find that "passive-RP" is a much more suitable term, as it describes roleplay that doesn't involve hostile action whilst avoiding conjuring up images of a group of people sitting near debug cooking wolf steak and telling the same generic backstories.
I'll post more/edit this post if I come up with more additions or points. Thank-you for opening this discussion in a concise and calm manner. Other threads haven't been so kind.